Arc-lamp safety device.



0. F. ASBURY.

ARC LAMP SAFETY DEVICE.

APPLICATION IILED was, 1909.

Patented Dec. 6, 1910.

X? z/ zww UNITED STATES PATENT OFFICE.

ORLA F. ASBURY, 01? CHARLOTTE, NORTH CAROLINA, ASSIGNOR OF ONE-HALF TODANIEL A. TOMPKINS, OF CHARLOTTE, NORTH CAROLINA.

ARC-LAMP SAFETY DEVICE.

T 0 all whom 'it may concern:

Be it known that I, ORLA F. AsBURY, a I

citizen of the United States, and resident of Charlotte, in the countyof Mecklenburg and State of North Carolina, have invented certain newand useful Improvements in Are- Lamp Safety Devices; and I do herebydeclare the following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which itappertains to make and use the same.

The invention relates to improvements in arc lamps, and is particularlyintended to provide means for preventing the upper or feeding carbonfrom short circuiting through the frame of the lamp when the lower carbon burns out or is displaced for any reason.

It frequently occurs that the lower or fixed carbon of an electric arclamp burns out or is displaced or broken, so that the upper carbon, inits feeding movement, makes contact with the metal frame of the lamp,more particularly with the socket or holder for the lower carbon, andestablishes an are which quickly burns out the metal of the frame andrenders the lamp useless.

The present invention is intended to provide an improved insulatingdevice, which, while the lower carbon is of proper length and occupiesits normal position, is held by said lower carbon in inoperativerelation, but when said carbon falls below a predetermined length or isdisplaced from its socket, said device is automatically projected intothe path of movement of the feeding carbon and between the end of thesame and the frame of the lamp, thereby supporting the feeding carbonand preventing the same making electrical contact with the lamp frame.

In the accompanying drawings, Figure 1 is a perspective view of thecarbons and the lower portion of an arc lamp, involving the invention.Fig. 2 is a side elevation of the same' Referring to the drawings, 1indicates the upper or feeding carbon of an arc lamp, and 2, the loweror stationary carbon. It will be understood that the upper carbon issecured in the lamp by the usual clutch mechanism to effect the strikingof the arc and trimming of the lamp in the usual manner. The lowercarbon 2 is supported in a socket 4;, at the lower end of the metalframe work 3,

Specification of Letters Patent.

Application filed February 8, 1909.

Patented Dec. 6, 1910.

Serial No. 476,646.

' said carbon 2 being rigidly held within the socket by means of a setscrew 5. Electrical contact is established between the lower carbon andthe socket 4 in the well known way and this under ordinary conditionshas the result that should said lower carbon burndown to the socket orbecome accidentally displaced while the current is on in the lamp, theupper carbon would establish a circuit and draw an are between its lowerend and the socket a, or the adjacent metal frame work of the lamp,which would quickly destroy the lamp frame or damage the same to such anextent as to render it incapable of further use. In order to obviatethis contingency, I provide a pivoted finger 8 which is preferably givena longitudinally curved form and tapers toward its free end, which isbroad and flat. Said finger 8 is pivoted in a vertical plane in a lug orextension 6 formed on or secured to one side of the socket 4:, thepivoting being effected by means of a pin 9 passing through two cars 7set into the lug 6, and a single car on the lower end of the finger 8.The finger is made of some refractory material best adapted for thepurpose, such as porcelain, indurated fiber or the like, and whenapplied to its proper position on the lamp frame normally tends toassume the posi tion indicated in Fig. 2 with its forward end overlyingthe socket and interposed in the path of movement of the feedingcarbon 1. hen the lower carbon is in position, the forward edge of thefinger 8 engages the side of the said lower carbon so that the finger isheld in the position indicated in Fig. 1.

Should the lower carbon burn to a point so that its upper edge fallsbelow the forward edge of the finger 8,. or should the lower carbon bebroken off or accidentally displaced, said finger 8 swings on its pivotunder the influence of gravity until its forward imperforate end isprojected between the lower end of the upper carbon and the upper end ofthe lower carbon, thereby shutting off the carbons from each other andrupturing the arc, whereby further downward movement of the upper carbonis prevented. Should the lower carbon be displaced or broken off flushwith the socket 4, the finger 8 swings below the upper carbon, andbecause of the fact that the movement of the finger 8 is limited by theengagement of shoulder 10 with the ears 7, as indicated in Fig. 2, theupper carbon will be held sufficiently far away from the socket or theadjacent metal work of the lamp frame to prevent an are beingestablished between said upper carbon and the metal work.

It will be noted that the device is entirely automatic in its operationand will be absolutely effective in preventing the establishment ofelectrical contact between the feeding carbon and the lamp frame.

Although I have illustrated a simple and preferred form of the device toeifeet the result stated, it will be understood that the device is notlimited to the form shown, but is capable of proper changes withoutdeparting from the spirit of the invention.

What I claim is 1. I11 an arc lamp, the combination with the carbons,and a fixed part of the lamp, of a vertically swinging member pivoted tosaid fixed part and operative to intercept the feeding carbon on theburning away or breaking of the fixed carbon.

In an arc lamp, the combination with the carbons, and a fixed part ofthe lamp, of a vertically swinging intercepting mem ber pivoted to saidpart and having its free end arranged to rest against and be supportedby the fixed carbon.

3. In an arc lamp, the combination with the holder of the fixed carbon,of a finger pivoted thereto to move in a vertical plane, and shiftableautomatically into the path of the feeding carbon when the fixed carbonis displaced or burned beyond a predetermined limit.

at. In an arc lamp, the combination with the upper and lower carbons, ofa pivoted finger movable in a vertical plane and arranged to rest ininclined position with its free end uppermost and against the lowercarbon.

5. In an arc lamp, the combination with the carbons, of a safety devicecomprising a pivoted finger mounted to extend at its free end betweenthe carbons and thereby intercept the feeding carbon, said finger beingcurved longitudinally and tapered to ard its free end.

(5. In an arc lamp, the con'ibination with the holder of the fixedcarbon, of a finger pivoted thereto to move in a vertical plane, saidfinger being curved longitudinally and tapered toward its free end.

7. In an arc lamp, the combination with the carbons, of an interceptingfinger fixedly pivoted and freely movable about its pivot, the free endof said finger being arranged to rest against the lower carbon, withsaid end above the pivot.

In testimony whereof I atfix my signature, in presence of two witnesses.

OKLA If. ASBURY.

IVitnesses G120. L. KRUEGER, H. A. HUNTLEY.

